Electronic, optical properties, surface energies and work functions of Ag₈SnS₆: First-principles method

Ternary metal chalcogenide semiconductor Ag₈SnS₆, which is an efficient photocatalyst under visible light radiation, is studied by plane-wave pseudopotential density functional theory. After geometry optimization, the electronic and optical properties are studied. A scissor operator value of 0.81 eV is introduced to overcome the underestimation of the calculation band gaps. The contribution of different bands is analyzed by virtue of total and partial density of states. Furthermore, in order to understand the optical properties of Ag₈SnS₆, the dielectric function, absorption coefficient, and refractive index are also performed in the energy range from 0 to 11 eV. The absorption spectrum indicates that Ag₈SnS₆ has a good absorbency in visible light area. Surface energies and work functions of (4 11), (413), (211), and (112) orientations have been calculated. These results reveal the reason for an outstanding photocatalytic activity of Ag₈SnS₆.